Primarily educated former samurai from the old tozama domains of Choshu and Satsuma, the oligarchs favored Westernization and modernization, overseeing the abolishment of the old feudalistic Han system, and encouraging rapid industrialization.

But despite the appearence of democratization, election of the prime ministers remained an imperial prerogative, and the oligarchs controlled the emperor. Thus in practice, the oligarchs selected whomever they wished to be the prime ministers. Moreover, they had cleverly assigned many important decisions as constitutionally reserved for the emperor, and thus in reality, the oligarchs made these decisions.

Around the turn of the century, a split emerged between two factions of oligarchs - one led by Ito and one led by Yamagata. The two factions maintained an uneasy balance for several years, trading offices and the premiership back and forth, until the conflict was alleviated over time primarily due to the deaths of many of the original oligarchs.

After the disastrous rice riots of 1918, the oligarchs relinquished direct control of the government to the popular political parties, initiating the so-called "Taisho Democracy", although Saionji Kimmochi, the last surviving oligarch, continued to excercise indirect control through his control of the House of Peers and essentially controlled who was named prime minister all the way up until the military takeover of 1932.